Genetic information and relationships - DNA & Protein synthesis

Question 1

Define the term gene

Answer 1

A base sequence of DNA that codes for the amino acid sequence of polypeptide and functional RNA

Question 2

What is the gene locus?

Answer 2

The specific position of a gene on a chromosome

Question 3

What is an intron

Answer 3

Non-coding sections of DNA and are found within genes

Question 4

What is an exon

Answer 4

Coding sections of DNA

Question 5

What are non-coding multiple repeats

Answer 5

Non-coding repeats of base sequences found between genes

Question 6

Why can much of eukaryotic DNA be considered as non-coding

Question 7

what are the proteins called that associate with eukaryotic DNA

Answer 7

Histone proteins

Question 8

Define the term chromosome

Answer 8

A condensed DNA molecule associated with histone proteins

Question 9

Describe the DNA in eukaryotes

Answer 9

• DNA molecules are longer
• DNA molecules are linear molecules
• DNA molecules are associted with proteins called histones

Question 10

Describe the DNA in prokaryotes

Answer 10

• DNA molecules are shorter
• DNA molecules are circular
• DNA molecules are not associated with histone proteins

Question 11

Describe the DNA in chloroplasts and chloroplasts

Answer 11

Circular DNA

Question 12

Why is the genetic code described as degenerate

Answer 12

Most amino acids are coded for by more than one triplet

Question 13

Why is the genetic code described as non-overlapping

Answer 13

Each base is only read once

Question 14

Why is the genetic code described as universal

Answer 14

Each triplet codes for the same amino acid in all organisms

Question 15

What is the genome

Answer 15

The complete set of genes in a cell

Question 16

What is the proteome

Answer 16

The full range (variety) of proteins that a cell is able to produce

Question 17

Differences between DNA nucleotide and an RNA nucleotide

Answer 17

• DNA (Deoxyribose sugar)
• RNA (Ribose sugar)
• DNA (Thymine)
• RNA (Uracil)
• DNA (Longer molecule)
• RNA (Shorter molecule)
• DNA (Double stranded)
• RNA (Single stranded)
• DNA (Base pairing)
• RNA (No base pairing)

Question 18

Structure of mRNA

Answer 18

• Straight chain
• Single chian
• Base sequence is complementary to DNA code

Question 19

Function of mRNA

Answer 19

Carries ‘code’ from nucleus to cytoplasm

Question 20

Structure of tRNA

Answer 20

• Clover leaf shape

Question 21

Function of tRNA

Answer 21

• Carries amino acids to the ribosomes
• Amino acid binding site

Question 22

What is a triplet code

Answer 22

A sequence of 3 DNA bases that code for a specific amino acid

Question 23

What is a codon

Answer 23

A sequence of 3 bases coding for an amino acid

Question 24

What is an anticodon

Answer 24

A sequence of 3 bases tht are complementary to the codon on mRNA

Question 25

What is pre-mRNA

Answer 25

MRNA that contains introns and exons

Question 26

What is splicing

Answer 26

Where the introns from the pre-mRNA are removed to eave a molecule of mRNA

Question 27

Describe how mRNA is formed by transcription in eukaryotes

Answer 27

- Hydrogen bonds between DNA bases break - Only one DNA strand acts as a template - Free RNA nucleotides align by complementary base pairing - RNA polymerase joins adjacent RNA nucleotides, forming posphodiester bonds - A bonds to Uracil instead of thymine - Pre-mRNA is splice to form mRNA

Question 28

Describe how a polypeptide is formed by the translation of mRNA

Answer 28

- mRNA attaches to ribosomes - tRNA anticodons bind to complementary mRNA codons - tRNA brings a specific amino acid - Amino acids join by peptide bonds with the use of ATP - tRNA is released after the amino acid is joined to the polypeptide - The ribosome moves along the mRNA to form the polypeptide